Pulmonary Stenosis

What is pulmonary stenosis?

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Pulmonary stenosis is a congenital (present at birth) defect that occurs due to abnormal development of the fetal heart during the first eight weeks of pregnancy.

The pulmonary valve is found between the right ventricle and the pulmonary artery. It has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle.

With pulmonary stenosis, problems with the pulmonary valve make it harder for the leaflets to open and permit blood to flow forward from the right ventricle to the lungs. In children, these problems can include:

• A valve that has leaflets that are partially fused together.

• A valve that has thick leaflets that do not open all the way.

• The area above or below the pulmonary valve is narrowed.

There are four different types of pulmonary stenosis:

• Valvar pulmonary stenosis. The valve leaflets are thickened and/or narrowed 

• Supravalvar pulmonary stenosis. The pulmonary artery just above the pulmonary valve is narrowed

• Subvalvar (infundibular) pulmonary stenosis. The muscle under the valve area is thickened, narrowing the outflow tract from the right ventricle

• Branch peripheral pulmonic stenosis. The right or left pulmonary artery is narrowed, or both may be narrowed

Pulmonary stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe pulmonary stenosis could be quite ill, with major symptoms noted early in life. A child with mild pulmonary stenosis may have few or no symptoms, or perhaps none until later in adulthood. A moderate or severe degree of obstruction can become worse with time.

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Pulmonary stenosis is a component of half of all complex congenital heart defects.

Pulmonary stenosis is the second most common congenital heart defect, comprising 5 to 10 percent of all cases.

What causes pulmonary stenosis?

Congenital pulmonary stenosis occurs due to improper development of the pulmonary valve in the first eight weeks of fetal growth. It can be caused by a number of factors, though most of the time this heart defect occurs sporadically (by chance), with no clear reason evident for its development.

Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families.

Why is pulmonary stenosis a concern?

Mild pulmonary stenosis may not cause any symptoms. Problems can occur when pulmonary stenosis is moderate to severe, including the following:

• The right ventricle has to work harder to try to move blood through the tight pulmonary valve. Eventually, the right ventricle is no longer able to handle the extra workload, and it fails to pump forward efficiently. Pressure builds up in the right atrium, and then in the veins bringing blood back to the right side of the heart. Fluid retention and swelling may occur.

• There is a higher than average chance of developing an infection in the valves of the heart known as bacterial endocarditis.

What are the symptoms of pulmonary stenosis?

The following are the most common symptoms of pulmonary stenosis. However, each child may experience symptoms differently. Symptoms may include:

• Heavy or rapid breathing

• Shortness of breath

• Fatigue

• Rapid heart rate

• Swelling in the feet, ankles, face, eyelids, and/or abdomen

• Fewer wet diapers or trips to the bathroom

The symptoms of pulmonary stenosis may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.

How is pulmonary stenosis diagnosed?

Your child's physician may have heard a heart murmur during a physical examination, and referred your child to a pediatric cardiologist for a diagnosis. A heart murmur is simply a noise caused by the turbulence of blood flowing through the obstruction from the right ventricle to the pulmonary artery. Symptoms your child exhibits will also help with the diagnosis.

A pediatric cardiologist specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood. The cardiologist will perform a physical examination, listening to the heart and lungs, and make other observations that help in the diagnosis. The location within the chest that the murmur is heard best, as well as the loudness and quality of the murmur (harsh, blowing, etc.) will give the cardiologist an initial idea of which heart problem your child may have. Diagnostic testing for congenital heart disease varies by the child's age, clinical condition, and institutional preferences. Some tests that may be recommended include the following:

• Chest X-ray. A diagnostic test which uses X-ray beams to produce images of internal tissues, bones, and organs onto film.

• Electrocardiogram (ECG or EKG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle stress.

• Echocardiogram (echo). A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.

• Cardiac catheterization. A cardiac catheterization is an invasive procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Contrast dye is also injected to more clearly visualize the structures inside the heart.

Treatment for pulmonary stenosis

Specific treatment for pulmonary stenosis will be determined by your child's physician based on:

• Your child's age, overall health, and medical history

• Extent of the condition

• Your child's tolerance for specific medications, procedures, or therapies

• Expectations for the course of the condition

• Your opinion or preference

Mild pulmonary stenosis often does not require treatment. Moderate or severe stenosis is treated with repair of the obstructed valve. Several options are currently available.

Some infants will be very sick, require care in the intensive care unit (ICU) prior to the procedure, and could possibly even need emergency repair of the pulmonary valve if the stenosis is severe. Others, who are exhibiting few symptoms, will have the repair scheduled on a less urgent basis.

Repair options include the following:

• Balloon dilation or valvuloplasty. An interventional cardiac catheterization procedure is the most common treatment choice. A small, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. The tube has a deflated balloon in the tip. When the tube is placed in the narrowed valve, the balloon is inflated to stretch the area open. This procedure may be used for valvar pulmonary stenosis or branch types of pulmonary stenosis. Children who have undergone balloon dilation will need to follow antibiotic prophylaxis for a specific period of time after discharge from the hospital.

• Valvotomy. Valvotomy is the surgical release of scar tissue within the aortic valve leaflets that are preventing the valve leaflets from opening properly.

• Valvectomy (with or without transannular patch). Valvectomy is the surgical removal of the valve and the widening of the outflow patch to improve blood flow from the right ventricle into the pulmonary artery. Once the individual reaches adulthood, the pulmonary valve is generally replaced.

• Patch enlargement. Patches are used to enlarge the narrowed areas. In subvalvar pulmonary stenosis, an incision is made into the right ventricle, muscle is divided causing the obstruction below the pulmonary valve, and a patch is sewn into the cut edges of the right ventricle to enlarge the area below the pulmonary valve where the narrowing used to be. In supravalvar pulmonary stenosis, the narrowing is in the artery just beyond the pulmonary valve. Patches are sewn into this artery to enlarge its diameter and relieve the narrowing.

• Pulmonary valve replacement. Replacement of the pulmonary valve is a surgical procedure that is often recommended in adulthood. A tissue valve (pig or human) may be used. Children who have undergone a valve replacement will need to follow antibiotic prophylaxis throughout their life.

Postprocedure care for your child

• Cath lab interventional procedure. When the procedure is complete, the catheter(s) will be withdrawn. Several gauze pads and a large piece of medical tape will be placed on the site where the catheter was inserted to prevent bleeding. In some cases, a small, flat weight or sandbag may be used to help keep pressure on the catheterization site and decrease the chance of bleeding. If blood vessels in the leg were used, your child will be told to keep the leg straight for a few hours after the procedure to minimize the chance of bleeding at the catheterization site. Your child will be taken to a unit in the hospital where he or she will be monitored by nursing staff for several hours after the test. The length of time it takes for your child to wake up after the procedure will depend on the type of medicine given to your child for relaxation prior to the test, and also on your child's reaction to the medication. After the procedure, your child's nurse will monitor the pulses and skin temperature in the leg or arm that was used for the procedure. Your child may be able to go home after a specified period of time, providing he or she does not need further treatment or monitoring. You will receive written instructions regarding care of the catheterization site, bathing, activity restrictions, and any new medications your child may need to take at home.

• Surgical repair. After surgery, your child will go to the intensive care unit (ICU). While your child is in the ICU, special equipment will be used to help him or her recover from surgery, and may include the following:

  • Ventilator. A  machine that helps your child breathe while he or she is under anesthesia during the operation. A small, plastic tube is guided into the windpipe and attached to the ventilator, which breathes for your child while he or she is too sleepy to breathe effectively on his or her own. Many children remain on the ventilator for a while after surgery so they can rest.

  • Intravenous (IV) catheters. Small, plastic tubes inserted through the skin into blood vessels to provide IV fluids and important medicines that help your child recover from the operation.

  • Arterial line. A specialized IV placed in the wrist, or other area of the body where a pulse can be felt, that measures blood pressure continuously during surgery and while your child is in the ICU.

  • Nasogastric (NG) tube. A small, flexible tube that keeps the stomach drained of acid and gas bubbles that may build up during surgery.

  • Urinary catheter. A small, flexible tube that allows urine to drain out of the bladder and accurately measures how much urine the body makes, which helps determine how well the heart is functioning. After surgery, the heart will be a little weaker than it was before, and, therefore, the body may start to hold onto fluid, causing swelling and puffiness. Diuretics may be given to help the kidneys remove excess fluid from the body.

  • Chest tube. A drainage tube may be inserted to keep the chest free of blood that would otherwise accumulate after the incision is closed. Bleeding may occur for several hours, or even a few days after surgery.

  • Heart monitor. A machine that constantly displays a picture of your child's heart rhythm, and monitors heart rate, arterial blood pressure, and other values.

  Your child may need other equipment not mentioned here to provide support while in the ICU, or afterwards. The hospital staff will explain all of the necessary equipment to you. Your child will be kept as comfortable as possible with several different medications; some of which relieve pain, and some of which relieve anxiety. The staff will also be asking for your input as to how best to soothe and comfort your child. After discharge from the ICU, your child will recuperate on another hospital unit for a few days before going home. You will learn how to care for your child at home before your child is discharged. Your child may need to take medications for a while, and these will be explained to you. The staff will give you instructions regarding medications, activity limitations, and follow-up appointments before your child is discharged.

Long-term outlook after pulmonary stenosis repair

Your child's cardiologist may recommend that antibiotics be given to prevent bacterial endocarditis for a period of time following surgery and always for all valve replacements.

Occasionally, repeat interventional cath lab procedures may be necessary during infancy and childhood to stretch the valve open. Replacement of the pulmonary valve is generally recommended later during adolescence or early adulthood to prevent complications such as enlargement of the right ventricle, heart failure, and dysrhythmias (irregular or fast heartbeats).

Regular follow-up care at a center offering pediatric or adult congenital cardiac care should continue throughout the individual's lifespan.

Consult your child's physician regarding the specific outlook for your child.